Field of the Invention
The present invention relates to a display apparatus and a method for controlling the same.
Description of the Related Art
In some display apparatuses such as liquid crystal displays using a backlight, the backlight is constituted by a plurality of light sources whose brightness is capable of being separately controlled. Such display apparatuses may improve display contrast by controlling the brightness of respective light sources according to input images and correcting the input images according to the brightness of the respective light sources (see, for example, Japanese Patent Application Laid-open No. 2008-51905). This technology is called local dimming. However, image correction may cause degradation in original input images due to influence by, for example, quantization error or the like.
Liquid crystal displays have also been used for interpretation with X-ray or mammography. In such medical image observation, it is required to faithfully display original input images for accurate diagnosis. However, if display images are degraded due to image processing, the faithful display of the images is not allowed.
In view of this problem, there has been proposed technology in which local dimming is applied only to light sources corresponding to background regions not to be observed and is not applied to light sources corresponding to object regions to be observed in input images (see, for example, Japanese Patent Application Laid-open No. 2013-148870). Thus, since black floating caused by light leaking from a liquid crystal display is prevented in dark background regions, an observer such as an interpretation operator may be free from the feelings of interference. In addition, since degradation due to image processing is prevented in object regions and input images are faithfully displayed, diagnosis with precision is made possible.